Oct 02, 2019
07:31 AM
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Oct 02, 2019
07:31 AM
Dear all,
I have a question regarding CMTI:
1) Why is CMTI important in a gate driver IC?
2) What CMTI is recommended?
Thanks in advance!
Gyro
I have a question regarding CMTI:
1) Why is CMTI important in a gate driver IC?
2) What CMTI is recommended?
Thanks in advance!
Gyro
Solved! Go to Solution.
1 Solution
Oct 04, 2019
06:15 AM
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Oct 04, 2019
06:15 AM
Dear Gyro,
when switching SiC-Mosfets with a strong driver, a low gate resistor value and low additional parasitic capacitance dV/dt values of 50..100 kV/us can be reached. This is good to minimize losses, but there are also detrimental effects on the system:
- a driver IC with insufficient CMTI might generate erroneous gate signals in case the internal signal transmission gets corrupted
- current spikes will be injected to the control side even across the smallest parasitic capacitance
If you anyhow limit dV/dt by larger gate resistors -e.g. in a drive application- of course also you driver will only see moderate stress.
Best regards,
electricuwe
when switching SiC-Mosfets with a strong driver, a low gate resistor value and low additional parasitic capacitance dV/dt values of 50..100 kV/us can be reached. This is good to minimize losses, but there are also detrimental effects on the system:
- a driver IC with insufficient CMTI might generate erroneous gate signals in case the internal signal transmission gets corrupted
- current spikes will be injected to the control side even across the smallest parasitic capacitance
If you anyhow limit dV/dt by larger gate resistors -e.g. in a drive application- of course also you driver will only see moderate stress.
Best regards,
electricuwe
1 Reply
Oct 04, 2019
06:15 AM
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Oct 04, 2019
06:15 AM
Dear Gyro,
when switching SiC-Mosfets with a strong driver, a low gate resistor value and low additional parasitic capacitance dV/dt values of 50..100 kV/us can be reached. This is good to minimize losses, but there are also detrimental effects on the system:
- a driver IC with insufficient CMTI might generate erroneous gate signals in case the internal signal transmission gets corrupted
- current spikes will be injected to the control side even across the smallest parasitic capacitance
If you anyhow limit dV/dt by larger gate resistors -e.g. in a drive application- of course also you driver will only see moderate stress.
Best regards,
electricuwe
when switching SiC-Mosfets with a strong driver, a low gate resistor value and low additional parasitic capacitance dV/dt values of 50..100 kV/us can be reached. This is good to minimize losses, but there are also detrimental effects on the system:
- a driver IC with insufficient CMTI might generate erroneous gate signals in case the internal signal transmission gets corrupted
- current spikes will be injected to the control side even across the smallest parasitic capacitance
If you anyhow limit dV/dt by larger gate resistors -e.g. in a drive application- of course also you driver will only see moderate stress.
Best regards,
electricuwe